1. Field of the Invention
The present invention relates to a battery pack which is rechargeable by a magnetic induction effect.
2. Description of the Related Art
A battery pack rechargeable by a magnetic induction effect is charged by using a contactless battery charger. The battery packs where a battery is rechargeable in such a method are disclosed in Japanese Laid-Open Patent Publication No. H09-063655 (1997) and Japanese Laid-Open Utility Model Publication No. S58-021968 (1983). The battery pack described in Japanese Laid-Open Patent Publication No. H09-063655 (1997) has a secondary coil disposed within its casing. The secondary coil, being provided in a flexible circuit board, is disposed inside the casing.
The battery pack described in Japanese Laid-Open Utility Model Publication No. S58-021968 (1983) has a secondary coil fixed, in a layered state, to the bottom of a tubular battery. The battery pack thus structured can be charged, being placed on the charger, without being connected to the charger via a connector. Such structure allows various models of battery packs to be set and charged on a single piece of charger. Further, the battery pack, being incorporated in a mobile electronic device, can also be set to charge the mobile electronic device. This feature allows, for example, various models to be applied, also facilitating a convenient charge when the charger is incorporated in a battery pack and a cellular phone, models of which are frequently changed.